Now, to a puzzling case in michigan, where two 20-year-olds were just doing their jobs at a dollar store in the suburbs. Now, one of them is dead. The other is missing. Authorities are searching for answers. And abc's linsey davis is here with the latest on this puzzling case. Really puzzling, indeed. Good morning to you, elizabeth. It's a case that is confounding authorities. But new surveillance video has emerged that police believe could provide the clues they've been searching for. He was a young man. He was happy about the job. He's smiling all the time. And it's just senseless. We have no idea. Reporter: The families of co-workers joe orlando and brenna machus is pleading for help this morning. She's loved by many. If there's someone out there that has her, I don't care if you drop her off at a hospital. Let us know. We will come get her. No questions asked. We want her home. Reporter: Just two days ago, authorities entered the family dollar store in dearborn, michigan, and found 20-year-old joe orlando dead on the floor of the ransacked store. Still missing, 20-year-old assistant manager, brenna machus. She hasn't been seen since. We want her home. Reporter: Police believe this man, caught on surveillance video in the star, is the primary suspect. In the footage, he's wearing a hooded jacket, and appears to wave at the camera on the way in. He arrived shortly before 7:30 monday night. Authorities are searching for two other women who were also in the store at that time. We're going to make sure we do everything we can to bring the family of joseph and brenna some closure and some justice. Reporter: There is an $11,000 reward for any information about brenna's whereabouts. Investigators are asking all of the victims' friends and family to talk to police, in the hopes that any information here will help. Brenna's mother, who called her daughter a shining star, says she wants her daughter back, no questions asked. And joseph orlando was just hired last week. Wow. One week on the job? Last week. I hope the police get some answers soon. Thank you so much.

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